Spatially refined satellite gravimetry captures human signatures in global terrestrial water storage trends.

September 22, 2026| Source: Proceedings of the National Academy of Sciences of the United States of America

Human activities have directly altered the water cycle through water management, aquifer pumping, agricultural irrigation, and land use change. Although satellite gravimetry has transformed global hydrological research, its coarse resolution limits attribution of freshwater change to human activities at many management-relevant scales. Here we assessed global terrestrial water storage (TWS) trends from April 2002 to November 2025 using "stacked" regression of Level-1B intersatellite ranging data, which leverages temporal information and variability to dramatically improve effective spatial resolution relative to standard approaches. We combined this refined product with rigorous uncertainty analysis, autocorrelation-robust geostatistical methods, and literature assessment to evaluate TWS trend associations with land and water use, climate variability, and glacial mass loss. We identified 40 TWS trend hotspots exhibiting significant spatial associations with anthropogenic drivers, including groundwater and surface-water irrigation, rainfed agriculture, deforestation, and reservoir impoundment. Across these regions, cumulative TWS losses (3,122 Gt) substantially exceeded gains (2,432 Gt). Compared with traditional regression of monthly mascons, our approach yielded regional trend magnitudes that are on average 33% larger, revealing that global freshwater depletion, particularly from groundwater pumping, is considerably more acute than previously estimated. Multivariate regression models show that humans account for a significant share of the spatial variability in TWS trends on every nonpolar continent except Australia. We detected localized TWS gains linked to rainfed agriculture, surface water irrigation, and reservoir filling that were unresolved in earlier gravimetric studies. The methodology provides a foundation for future gravity missions to independently track decadal freshwater change with unprecedented spatial fidelity.

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Nutrient legacies from elephant megacarcasses create coldspots of biodiversity and hotspots of ecosystem processes.

Terrestrial megafauna (animals >1,000 kg) have substantial impacts on ecosystems while alive; yet, we know little about the impacts of these ecosystem engineers after they die. Like whale carcasses in the ocean, terrestrial megacarcasses may leave ecological legacies via the nutrient pulses they create on the landscape. Here, we investigated the impact of elephant megacarcasses on savanna ecosystems in Kruger National Park, South Africa. To determine how elephant carcasses affect below- and a

EnvironmentOctober 27, 2026

Global origins of tuna and billfish fisheries reveal the transition from coastal access to oceanic exploitation.

Ocean ecosystems have played a crucial role in people's lives around the world for millennia. However, questions persist about when, why, and how people first began removing biomass from offshore habitats and established fisheries in distant, oceanic environments. We explore the antiquity and evolution of tuna (Thunnini) and billfish (Istiophoridae/Xiphiidae) fisheries, two groups of fishes that occur around the world, are economically significant, and are ecologically important open ocean apex

EnvironmentOctober 20, 2026

Maternal ranging strategies facilitate offspring social play at energetic cost in the most solitary ape.

In most vertebrates, social play among peers is considered essential for behavioral development. Yet in solitary species bearing single offspring, opportunities for social play are inherently scarce. Whether mothers of such species actively facilitate play opportunities for their offspring, and at what cost, remains unknown. We used 15 y of behavioral and movement data (∼32,600 observation hours) from 31 wild Bornean orangutan ( Pongo pygmaeus wurmbii ) mother-offspring pairs to test whet

EnvironmentOctober 20, 2026

Evolution shapes ecosystem resilience through spatial self-organization.

Drylands are globally widespread and ecologically important but vulnerable to climate change. Many exhibit spatially self-organized vegetation patterns that enhance resilience by enabling vegetation to reorganize their patterns under drying, thereby optimizing water use and maintaining productivity. Plants can also undergo evolution in response to environmental change. Although both spatial self-organization and rapid evolution are fundamental mechanisms of resilience, their interaction remains

EnvironmentOctober 20, 2026

Thermal imbalance drives avian performance and responses to climate warming.

Thermal performance curves are widely used to predict ectothermic responses to climate warming but are less effective for predicting endotherm performance across environmental conditions because thermoregulation often decouples body temperature from ambient temperature. We develop theory and provide empirical evidence for performance curves in endotherms structured by net sensible heat flux (Q), an integrative index of thermoregulatory imbalance. Using biophysical simulations in tree swallows, w